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blit_transparent_rle.cpp

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/*
        ------------------------------------------------------------------------
        ClanLib, the platform independent game SDK.

        This library is distributed under the GNU LIBRARY GENERAL PUBLIC LICENSE
        version 2. See COPYING for details.

        For a total list of contributers see CREDITS.

        ------------------------------------------------------------------------
*/

#include "Core/precomp.h"
#include <Display/Display/Generic/blit_transparent_rle.h>
#include "API/Display/Display/surfaceprovider.h"

CL_Blit_Transparent_RLE::CL_Blit_Transparent_RLE(
        CL_SurfaceProvider *provider,
        int bytes_per_pixel)
{
        width = provider->get_width();
        height = provider->get_height();
        no_sprs = provider->get_num_frames();

        this->bytes_per_pixel = bytes_per_pixel;
        
        rle_lines = new unsigned char*[height*no_sprs]; 
}


CL_Blit_Transparent_RLE::~CL_Blit_Transparent_RLE()
{
        for (int y=0; y<height; y++) delete[] rle_lines[y];
        delete[] rle_lines;
}


int CL_Blit_Transparent_RLE::calc_rle_size(unsigned char *alpha_line)
{
        int size = 0;
        
        int last_state = cmd_end;
        for (int x=0; x<width; x++)
        {
                switch(alpha_line[x])
                {
                case 0 :   // transparent pixel         
                
                        if (last_state != cmd_skip) size += 3; // cmd_skip+word
                        last_state = cmd_skip;
                        break;
                
                case 255:  // opaque pixel
                
                        if (last_state != cmd_copy) size += 3; // cmd_skip+word
                        last_state = cmd_copy;
                        size += bytes_per_pixel;
                        break;
                
                default:   // alpha value
                        
                        if (last_state != cmd_alpha) size += 3; // cmd_alpha+word
                        last_state = cmd_alpha;
                        size += bytes_per_pixel + 1; // pixel data + alpha value
                        break;
                }       
        }
        
        size++; // cmd_end
        
        return size;
}


void CL_Blit_Transparent_RLE::blt_noclip(
        CL_Target *target,
        int x,
        int y,
        int spr_no)
{
        target->lock();
        
        unsigned int dest_bytes_per_pixel = (target->get_depth()+7)/8;
        unsigned int dest_pitch = target->get_pitch();
        unsigned char *dest = (unsigned char *) target->get_data();

        dest += x*dest_bytes_per_pixel + y*dest_pitch;

        int begin = height*spr_no;
        for (int yy=0; yy<height; yy++)
        {
                blt_line(rle_lines[yy+begin], dest);
                dest += dest_pitch;
        }

        target->unlock();
}

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